编写网络寻呼机
1、在VB中编写网络寻呼机需要建立两个程序，一个为客户端程序Client，一个为服务器端程序Server。 一、在Client工程中建立一个窗体，加载WinSock控件，称为tcpClient，协议选择TCP。再加入四个文本框，用以输入服务器的IP地址、服务器端口号，被呼叫的网络寻呼ID号以及用户登录ID号。然后再在窗体中加入三个按钮，分别命名为“连接”、“断开”和“退出”，点击“连接”按钮，并进行如下初始化连接，代码如下：
2、Private Sub Command1_Click() If Len(Text1.Text) = 0 An颊俄岿髭d Len(Text2.Text) = 0 Then MsgBox ("请输入主机名或主机IP地址。") Exit Sub ElseIf Len(Text1.Text) > 0 Then tcpClient.RemoteHost = Text1.Text tcpClient.RemotePort = Text2.Text End If tcpClient.Connect Timer1.Enabled = TrueEnd SubPrivate Sub Command2_Click() tcpClient.Close '断开连接End SubPrivate Sub Command3_Click() EndEnd SubPrivate Sub Form_Load() Text2.Text = "1001"End SubPrivate Sub tcpClient_Connect() tcpClient.SendData (Text3.Text&"@"&Text4.Text)End SubPrivate Sub tcpClient_DataArrival(ByVal bytesTotal As Long) Dim strData As String tcpClient.GetData strData strData = strData + "呼叫" '在收到呼叫消息后弹出一对话框并显示主叫方ID号码 MsgBox (strData)End Sub
3、二、在服务器端Server工程中也建立一个窗体，加载WinSock控件，称为tcpServer，协议选择TCP，设置其Index值为0，并在工程中添加模块。内容如下：Private Type ActiveUser ClientIP As String '记录客户的IP地址 ClientPort As Integer '记录当前会话的端口 ClientID As Long '记录客户的ID号码 ClientConnected As Boolean '客户连接状态，True表示已连接，False表示没有连接End TypeDim CurUser() As ActiveUserDim tcpIndex As Integer '跟踪当前建立连接数
4、在Form_Load事件中加入如下代码：Private Sub Form_Load() tcpServer(0).Protocol = sckTCPProtocol tcpServer(0).LocalPort = 1001 '将 LocalPort 属性设置为一个整数。 tcpServer(0).Listen '然后调用 Listen 方法。 tcpIndex = 1End Sub
5、准备应答客户端程序的请求连接，使用ConnectionRequest事件来应答户端程序的请求，代码如下：Private Sub tcpServer_ConnectionRequest(Index As Integer, ByVal requestID As Long) Dim i As Integer On Error GoTo ErrHandle For i = 1 To tcpIndex '选择一个空闲端口 If CurUser(i).ClientConnected = False And i < > tcpIndex Then Load tcpServer(i) tcpServer(i).LocalPort = CurUser(i).ClientPort - 1 tcpServer(i).Accept requestID Exit For ElseIf CurUser(i).ClientConnected = False Then Load tcpServer(i) tcpServer(i).LocalPort = Port If tcpServer(i).State < > sckClosed Then tcpServer(i).Close End If tcpServer(i).Accept requestID Exit For End If Next DoEvents
6、'测试连接是否成功 If tcpServer(i).State = sckConnected Then If i = tcpIndex Then '已经没有可用端口,记录客户的IP地址和端口号 tcpIndex = tcpIndex + 1 Port = Port + 1 ReDim Preserve CurUser(tcpIndex) CurUser(i).ClientIP = tcpServer(i).RemoteHostIP CurUser(i).ClientConnected = True CurUser(i).ClientPort = Port CurUser(tcpIndex).ClientConnected = False Else CurUser(i).ClientIP = tcpServer(i).RemoteHostIP CurUser(i).ClientPort = Port CurUser(i).ClientConnected = True End If End If Exit Sub ErrHandle: Resume Next
7、 争犸禀淫'检查控件的 State 属性,如未关闭，在接受新的连接之前关闭此连接。 If tcpServer(0).State <> sckClosed The荏鱿胫协n tcpServer(0).Close tcpServer(0).Accept requestID '接受具有 requestID 参数的,连接。End SubPrivate Sub tcpServer_DataArrival(Index As Integer, ByVal bytesTotal As Long) Dim i As Integer Dim s As String Dim RequID As Long '主叫方ID号码 Dim SearchID As Long '被叫方ID号码 On Error GoTo ErrHandle tcpServer(Index).GetData s, vbString '接收数据并存入s If Mid(s, i, 1) = "@" Then '分离s中的主叫方和被叫方ID号码 SearhID = Left(s, i - 1) '把号存入mKey RequID = Right(s, Len(s) - i) 'ID存入RequID End If '如果是请求寻呼某一ID号码,则检索当前此ID用户是否登录（即CurUser数组中是否存在此用户）,然后发送信息，通知此用户响应呼叫并显示主叫用户ID号码。 For i = 1 To tcpIndex If RequID = CurUser(i).ClientID And CurUser(i).ClientConnected = True Then tcpServer(i).SendData (SearhID) End If Next Exit Sub ErrHandle: If Err.Number = sckBadState Then '连接不正确 CurUser(i).ClientConnected = False CurUser(i).ClientIP = "" Unload tcpServer(i) Resume Next End IfEnd Sub
